Warrington pair Simon Grix and Ryan Atkins and Hull KR's Blake Green have all been cautioned by the Rugby Football League disciplinary committee.
The trio were cited during the weekend's Challenge Cup quarter-finals.
Half-back Grix was punished for gripping Wigan forward Lee Mossop by the neck, and centre Atkins for a dangerous tackle on Mossop.
Rovers half-back Green has been cautioned for "flipping" St Helens' second-row Jon Wilkin in a tackle.
The RFL said the cautions would "remain on the players' records and could be considered in the event of future disciplinary breaches."